Body size range

On Mar 30, 2005, at 8:37 PM, Geoff Read wrote:
>> I am currently developing a chapter on patterns of body size for marine
>> invertebrates for upcoming volume on patterns of body size.
> Hello,
>> Since this is your field of expertise, would you be able to educate
> annelida listers with an idea of why this is interesting to you and what
> factors are important? I imagine maxima are controlled by more than just a
> 'limit to growth' due to physiological constraints on a body plan, but it
> is a long time since I was at uni having this stuff explained. Are there
> existing books, reviews?
>> Geoff
> (annelida moderator)
There are number of reasons. First geographic patterns in body size have
recieved little attention in invertebrates (especially marine invertebrates)
except for insects. The work on body size in mammals, birds, reptiles, and
amphibians is enormous. Yet, many hypotheses about what limits body size are
presented as generalities, without test of them among the inverts. Take for
example the volume I am contributing a chapter to...there are entire chapters
about body size of mammalian orders but two on inverts (mine on marine inverts
and one on insects by Gaston and Chown). At first this may seem biased, yet
the research to synthesize on body size patterns in marine invertebrates is
just lacking. Knowing what limits body size also speaks to what may be
limiting ranges, diversity, abundance, biomass, and host of other ecological
variables. To specifically address your question why are size ranges
important. One, only general textbooks on inverts. present this kind of
information yet what they present is very vague and lacking for some groups.
Perhaps more importantly, it begins to address what constrains size in
different groups and the enormous variation in size in these groups. Take for
example the group I typically work with. The size range for marine gastropods
is much larger than terrestrial gastropods. At the upper end the ease at
which a large, heavy shell can be carried submerged underwater is much greater
than can be carried on land. At the lower end, small terrestrial snails are
much more prone to desiccation, yet marine snails can occupy smaller sizes
because of living in the aquatic medium. I urge your readers (can you forward
this along to the listserv) to share their thoughts on body size in annelids
with me (including limits to size, geographic variation in size, and the
largest and smallest species).
-Craig
____________
Craig R. McClain, Ph.D.
Department of Biology
University of New Mexico
MSC03 2020
Albuquerque, NM 87131-0001
phone: 505-277-6437
email: mcclainc at unm.edu
website: http://biology.unm.edu/crmcclain/
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